If the tranny has over 150k miles then I would rebuild it. The rubber that is failing for one seal is the same age as all the other seals inside and out.
Proper front seal replacement including the pump O-ring require partial disassembly anyway. Right at about half the labor to do the whole thing. Its like rolling the dice. Odds are it will be apart within 50-75k for something else if not sonner.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician